JPS5870643A - Receiver for car - Google Patents

Abstract

PURPOSE:To improve the sound quality of reception, by providing an antenna on a front glass of a car to perform space diversity reception. CONSTITUTION:A front glass 1 of a car is provided with the 1st antenna 2 along the upper side and the 2nd antenna 3 along the lower side, and both antennas are connected to an antenna selection switch circuit 11. The circuit 11 is automatically switched with a reception level detection signal and an FM multi-path distortion detection signal (to detect distortion of a stereo pilot signal of 19kHz) to select the antenna for better reception.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a receiving device using a glass antenna for radio reception, etc. provided on a window glass of an automobile, and is particularly suitable for use in a receiving system of a diversity receiving system.

When a moving car receives radio waves such as FM broadcasts, there are periodic 7-A/G waves that occur because the field strength of the received radio waves fluctuates in the direction of travel, and multi-noise waves that occur as the receiving point moves. Received sound quality is likely to deteriorate due to factors such as temporal variations in arm distortion, and in particular, received sound may be interrupted in short intervals, making it difficult to recognize the received content.

The present invention provides a receiving system that can solve this problem. 1. In particular, it is possible to effectively perform space diversity reception, and the arrangement of the window glass antenna, which rarely blocks the driver's view, is improved. This is what we provide.

Embodiments of the present invention will be described below with reference to the drawings.

In the present invention, a pair of antenna wires are enclosed in a window glass on the front side of an automobile, and the antenna wires are used to perform signal reception. These antenna lines may be, for example, a Goupole-like antenna, a semi-folded dipole-like antenna, or a single-element antenna, with one antenna line running along the top edge of the front windshield and the other antenna line running along the top edge of the front windshield. are placed along the bottom edge of the window glass.

FIG. 1 shows a front view of a windshield of an automobile and an electric circuit diagram showing a first embodiment of the present invention.

In Figure 1, there is a semi-folded Goupole-like antenna (2) along the top edge of the windshield (1).
A second Goupole-like antenna (3) is provided along the lower edge. Each antenna (21 (31
A copper wire or the like is used as the wire material constituting the wire, and is wired in the first t4 turn on a laminated glass interlayer film in which a plurality of glass plates are laminated with an adhesive interlayer film.

In the case of a windshield, the wiring position and number of antenna wires are regulated so that the antenna wires do not obstruct the driver's view. For example, in the Automobile Manufacturers Association regulations or CHP regulations, as shown in the front view of the windshield in Figure 2, an area of 100suc from each side and 100B on both sides of the center line (
It is possible to wire at most two wires only in 4), and there is a regulation that an antenna element must not be placed in the shaded area (51). Turn satisfies this regulation.

Conventionally, it is known that this type of antenna wire is provided on the rear window glass of a car, but the rear window glass is often provided with multiple heater wires to prevent fogging.
The directivity characteristics of the antenna are greatly affected by these heater stripes, and a large 7° deviation is likely to occur particularly in the front-rear direction of the vehicle.For this reason, an extremely complex antenna pattern is required to reduce the dip in the directivity characteristics. The area occupied by the antenna wire was large. On the other hand, if the antenna wire is provided on the windshield as in this embodiment, the influence of the heater wire can be avoided, and good directivity characteristics can be obtained even with a relatively simple antenna pattern as shown in Figure 1. can.

In addition, if the two antennas (2) and (3) are installed along the top and bottom sides of the windshield as shown in Figure 1, the movement of the driver's eyes will be in roughly the same direction (horizontal direction), so the vertical Even when a (vertical) antenna element is provided, visibility is less likely to be obstructed.

It should be noted that if a vertical antenna element is provided on the windshield (particularly in the center), the element will enter the field of view of the 7-ender camera, which is undesirable.

Furthermore, as in the embodiment shown in FIG. 1, by providing the first antenna (2) on the upper side of the windshield (1), the received electric field strength can be increased at a position further away from the ground surface force! 1
1. It is possible to receive signals in a strong state, and high-quality reception errors can be obtained. Furthermore, FMi (70-90MHz) 7! with semi-folded Guypol antenna (2)! :When receiving, a length of '/2 (approximately 2m) is required,
- By providing this antenna (2) along the long side (upper side) of the windshield (1), it becomes possible to fully satisfy the above length.

Connect the lead wire to the receiver of the wire rod.

A notch (6) is formed in one glass plate of laminated glass, and a terminal fitting is inserted in that part.

1st and 2nd antenna (2) (output of 31 respectively lead wire (7) I8) 'ir through preamplifier (9)
<1 (I), and in order to perform diversity reception, one of the better received signals is selected by the selection switch circuit αυ and supplied to the FM receiver.

In addition, the first and second antennas (2) (31 lead wires (7) and (8) ld are short-circuited by an inductance element that has high impedance at the FM frequency break and low impedance at the AM frequency break, and is The AM reception output is taken from the tap and supplied to the AM receiver via a preamplifier (121).

As the lead wire (7) of the first antenna (2), an unbalanced coaxial wire (141) as shown in Fig. 3 can be used. can be directly fed to the unbalanced coaxial III (141) from the lead wire (141) of the second antenna (3).
As for 8), a parallel two-wire feeder or a single wire connected to the pair of terminals can be used.

When a coaxial line a9 is used as shown in FIG. 6, a balun circuit ue for balanced/unbalanced conversion is used to couple the antenna terminal and the coaxial line.

FIG. 4 is a block circuit diagram of the FM receiver used in this embodiment. In FIG. 4, the first antenna (2
)' or the received signal received by the second antenna (3) is selected by the changeover switch circuit αυ also shown in FIG. 1, and is supplied to the front end and the IF circuit. The received signal that has undergone tuning amplification, intermediate frequency conversion, and FM detection in this front end and IF circuit ■ is
The signal is supplied to the multiplexer (B) through a high-frequency cut control filter (C) and a noise plunker (C), where it is stereo demodulated and output from the R channel and the output terminals of the R channel to the audio power intensifier. A control signal C such as a stereo/mono-sil automatic switching signal is applied to the multiplexer (b) from an IF circuit (incorporated).

The reception signal level is detected (level detection of IF output or detection output) in order to mute the detuning noise between stations in the front end and IF circuit, and when the reception level reaches a certain level. The detection output is muted when the signal drops. This reception signal level detection signal a is given to a mute drive circuit within the IF circuit and is also sent to an automatic level setting circuit (e).

This automatic level setting circuit has a function of changing the threshold of the switching input level according to the switching frequency of the switch circuit Uυ, and this threshold is below +7
), a detection signal is generated. This detection signal is sent to an antenna switching control circuit, where a switching signal d is formed in synchronization with a clock of about 100 KHz output from a clock generator. This switching pulse d is T type 7
It is applied to the trigger input of the lip flop c3a, and the output (Q, Q) of the 7 lip flop 0υ is inverted by the trigger.

The Q output and the Q output of 7 Ritsuzo Flotsuzo C1υ are used as a switching control signal for the switch circuit aυ, and for example, when the received signal level of the first antenna (2) is lower than the set reference value, the flip-flop 0 is inverted. Then, the Q output becomes a low level, and the Q output becomes a high level and is switched to the antenna output of the second antenna (3).

The Q output of the flip-flop (31) is also provided with an automatic level setting circuit (E) K, and this circuit is connected to the second antenna (3).
The operating mode is switched to detect a decrease in the received level of the signal. Therefore, next time the reception level of the second antenna (3) drops below the set reference level, the automatic level setting circuit () detects this, and based on its detection output bK, the antenna switching control circuit () switches the I4 signal. d is generated again, and the 7-lip 70-tube Sυ is inverted by the /4' pulse d. Therefore, the switch circuit qυ is switched to the first antenna (2) side.

As a result, diper/tee reception is performed in which the antenna output is always switched to a higher antenna output than the set level of the reception level.

Furthermore, in the embodiment shown in FIG. 4, variations in multipath distortion are detected and reception can be performed by switching to the antenna output with less distortion. That is, the outputs of the front end and IF circuit are also supplied to the 19KHz CD pantono and filter C32, where the stereophono and illustration signals are extracted. This 7P pilot signal is given to the level fluctuation detection circuit (to). If the received signal is distorted by the 4L multipath, the Yailot signal will also be distorted, so by detecting the O level variation (distortion component variation).

It is possible to detect increases and decreases in multi-thousand distortion due to movement of the receiving point.

When the multipath distortion increases by a certain amount or more, the output e of the level fluctuation detection circuit Q operates the high frequency cut control filter (E), and the high frequency distortion component of the detection output is cut and given to the multiplexer). .

At the same time, the output e of the level fluctuation detection circuit (to) is also sent to the antenna switching control circuit, and the switching and
signal d is formed and switched to the other antenna output in the same way as in the case of received level fluctuations.

A received signal with less multipath distortion can be obtained by the lag. In the antenna switching control circuit (2), a switching/main line (d) is formed when either one of the outputs (S) and (e) of the automatic level setting circuit (1) and the level fluctuation detection circuit (2) is input. In other words, the signal d is switched by the OR logic with the signal d.
is created. Also, to prevent antenna switching due to reception level fluctuations when selecting a channel, 70/toend and 1. The reception level detection signal a obtained from the F circuit is given to the antenna switching control circuit I as an operation prohibition signal, thereby inhibiting the formation of the switching pulse d in the weak electric field area between stations during tuning. .

According to the embodiments shown in FIG. 1 and FIG.
Since the variation status of the reception level of each antenna is different due to the difference in the arrangement position of the antennas, it is possible to select the reception output of the better one to perform space diversity reception that minimizes the influence on reception sound quality. can.

Generally, when an antenna wire is installed on the window glass of a car, it exhibits directivity with a large dip in the front-rear direction, as shown by the solid line in the directivity characteristic in FIG. 5, due to the influence of the vehicle's daylight. However, as is well known, a dipole antenna placed in free space has strong directivity in the direction of direct firing with the element, and exhibits a figure-eight characteristic as shown in the single-dot chain IT in FIG.

Therefore, if you install the Guipole-like antenna t-windshield, 7j? Due to the influence of D, it is possible to obtain a directivity characteristic with less dip as indicated by the dotted line j in FIG.

In particular, when a semi-folded dipole-like antenna (2) as shown in the practical example shown in FIG. 1 is used, a nearly circular omnidirectional characteristic can be obtained.

6A to 6C show actual measurement data of the directivity characteristics of the semi-folded dipole-like antenna (2) shown in FIG. 1. The dimensions of the antenna (2) used to measure this data are that the horizontal length of the folded part is 11,000 mm, and the distance between parallel lines is 2 mm.
O-IX, the distance from the upper side of the windshield (1) to the folded portion is 120B. Measurements were also made for horizontally polarized waves, with A in Figure 6 being 76 MHz, B being 84 MHz,
C is 90MHz.

Next, FIGS. 7 to 10 are plan views of a windshield similar to FIG. 1, showing various modifications of the antenna pattern that can perform the viracity reception of this embodiment.

Figure 7 shows the semi-folded dipole-like antenna (2) and dipole-like antenna (31) in Figure 1 upside down, and Figure 8 shows the semi-folded dipole-like antenna (2) and the dipole-like antenna (31) in Figure 1. In combination with the single element antenna (3), Fig. 9 shows the antenna (21 (31) in Fig. 8 with its vertical position reversed. Also, in Fig. 10, the first and second antennas (2+ ( 31 are both constructed of semi-folded dipole-like antennas.

It should be noted that the antenna patterns of the embodiments shown in FIGS. 1 to 10 may be arranged in a row and reversed left and right with respect to the vertical center line of the window glass. Further, either one of the antennas (2) and (3) in FIG. 10 may be reversed left and right.

As described above, the present invention provides the first and second antennas on the windshield of the automobile, and detects the reception status of these radio waves and switches to receive the radio waves, thereby achieving a unique space diversity reception. In particular, it is possible to obtain a high-quality received signal in which the influence of fluctuations in reception level (fading) that occur due to movement of the reception point is reduced. In addition, since each of the first and second antennas is composed of horizontal elements along the upper and lower sides of the front glass,
Since the spatial distance between the second antenna and the second antenna is close to each other, space diversity reception can be effectively performed, and the driver's field of vision is not obstructed.

[Brief explanation of the drawing]

Fig. 1 is a front view and electric circuit diagram of an automobile windshield showing one embodiment of the present invention, Fig. 2 is a front view showing the restricted area of the antenna wiring position of the windshield, and Fig. 6 is the same as Fig. 1. 4 is a block circuit diagram of an FM receiver used in the present invention, FIG. 5 is a directivity characteristic diagram of an automobile window glass antenna, and FIGS. 6A to C are Semi-folded and semi-folded in Figure 1 respectively.
Directional characteristic diagram of dipole-like antenna, whistle figures 7 to 10
FIG. 1 is a front view of a front crow showing various modifications of the antenna pattern shown in FIG. 1. In the symbols used in the drawings, (1)...
・・・・・・・・・・・・ Windshield (2)・・
・・・・・・・・・・・・First antenna (3)・・
・・・・・・・・・・・・Second antenna aυ...
・・・・・・・・・・・・Changing switch circuit－・・・・
・・・・・・・・・Automatic level setting circuit■・・・・
・・・・・・・・・・・・Antenna switching control circuit. Agent Souvenir Masaru

Claims (1)

[Claims] Front of a car - A first plate installed along the top of the glass.
a second antenna line provided along the lower side; means for detecting the radio wave reception state 4 of the first and second antenna lines; Or a receiving device for an automobile, each comprising a changeover switch means for selecting and receiving a second antenna line.